Antifungal medicinal compositions

ABSTRACT

An object of the present invention is to provide a medicinal composition useful for external application in the treatment of a fungal infection reaching the lower part of a thick keratin layer. Provided is an antifungal medicinal composition, comprising: (1) a film-forming agent; (2) a water-soluble plasticizer in a form of a solid or a paste at 20° C. at 1 atm; and (3) an antifungal compound represented by a general formula (1) and/or a physiologically acceptable salt thereof.

TECHNICAL FIELD

The present invention relates to a medicinal composition, and morespecifically to a medicinal composition useful in the treatment andprevention of fungal diseases.

BACKGROUND ART

Fungal diseases represented by athlete's foot, vaginal candidiasis, andso on were formerly the diseases difficult to be completely cured, sothe treatment of athlete's foot has been a theme of eternity.

In recent years, bifonazole and other various drugs such as butenafineand terbinafine have been developed, allowing general cutaneous fungaldiseases such as athlete's foot to be completely cured. Among the fungaldiseases, however, one invaded in the thickened or excessivelykeratinized portion of a nail or skin remains almost impossible to betreated with the external application of a drug because of thedifficulty of allowing the drug to be transdermally delivered to thatportion. Therefore, the treatment of such a fungal disease has been onlyconducted by means of a method involving orally administering anantifungal agent such as terbinafine for as long as several months. Suchoral administration is systemic, so it will involve a great economicburden when it is prolonged. Besides, the above administration has beendifficult to be applied on tinea unguium having a little influence on ahuman life because of an increase in possibility of causing side effectsor the like.

In other words, the conventional method has been insufficient to beapplied as a therapeutic procedure with external administration of adrug on a fugal disease invaded in the bottom portion of thick keratinsuch as the inside of a thickened or extensively keratinized portion ofa nail or skin. Therefore, development of a medicinal composition usefulfor an external treatment of the fungal disease invaded in the bottomportion of such thick keratin has been demanded.

On the other hand, the compound represented by the general formula (1)to be described latter has been known to have an antifungal action.However, no technology, which utilizes such a compound as a principalingredient to prepare an antifungal preparation for tinea unguium or fortinea in the thickened portion of heel or the like, has been known inthe art at all.

Furthermore, no idea for obtaining an antifungal medicinal compositionby combining the antifungal compound represented by the general formula(1) and a specific film-forming agent or a water-soluble plasticizer inthe form of a solid or paste at 20° C. at 1 atm has been known in theart at all. Besides, the fact that the antifungal medicinal compositioncomposed as described above will be useful in the treatment of tineaunguium and the fungal diseases in the excessively keratinized portionor thickened portion of the skin has not been known at all.

DISCLOSURE OF THE INVENTION

The present invention has been made under such circumstances and intendsto provide a medicinal composition useful for external application inthe treatment of a fungal infection reaching the lower part of a thickkeratin layer.

In consideration of such circumstances, the inventors of the presentinvention have dedicated efforts to the study of obtaining a medicinalcomposition useful for external application in the treatment of a fungalinfection reaching the lower part of a thick keratin layer.Consequently, the inventors of the present invention have completed thepresent invention by finding out that an antifungal medicinalcomposition characterized by including (1) a film-forming agent, (2) awater-soluble plasticizer in the form of a solid or a paste at 20° C. at1 atm, and (3) an antifungal compound represented by the followinggeneral formula (1) exert such characteristics.

In other words, the present invention is constructed as described below.

(1) An antifungal medicinal composition, comprising: (1) a film-formingagent; (2) a water-soluble plasticizer in the form of a solid or a pasteat 20° C. at 1 atm; and (3) an antifungal compound represented by ageneral formula (1) and/or a physiologically acceptable salt thereof.

(In the formula, R represents an alkyl group having 1 to 8 carbon atoms,a cycloalkyl group having 3 to 6 carbon atoms, a methylene group, alower alkenyl group, a halogen atom, a lower alkyl group substitutedwith a lower alkoxy group or a lower alkylthio group, or a grouprepresented by a general formula (2) below.)

(In the formula, R₁ represents a hydrogen atom, a halogen atom, alinear- or branched-chain lower alkyl group, a lower alkoxy group, ahaloalkoxy group, or a methylenedioxy group, and m represents anintegral number of 1 to 3.)

-   (2) The antifungal medicinal composition according to (1), wherein    the firm-forming agent has low water solubility or water    insolubility.-   (3) The antifungal medicinal composition according to (2), wherein    the film-forming agent having low water solubility or water    insolubility comprises one or two or more selected from the group    consisting of ethyl cellulose, hydroxypropyl methylcellulose    phthalate, and an acrylic resin emulsion.-   (4) The antifungal medicinal composition according to (2), wherein    the film-forming agent having low water solubility or water    insolubility comprises ethyl cellulose.-   (5) The antifungal medicinal composition according to any one of (1)    to (4), wherein the water-soluble plasticizer in the form of a solid    or a paste at 20° C. at 1 atm comprises a compound having a    polyoxyethylene group and/or a polyoxypropylene group.-   (6) The antifungal medicinal composition according to (5), wherein    the water-soluble plasticizer in the form of a solid or a paste at    20° C. at 1 atm comprises an oxyethylene oxypropylene copolymer.-   (7) The antifungal medicinal composition according to (5), wherein:    the film-forming agent having low water solubility or water    insolubility comprises one or two or more selected from the group    consisting of ethyl cellulose, hydroxypropyl methylcellulose    phthalate, and an acrylic resin emulsion; and the water-soluble    plasticizer in the form of a solid or a paste at 20° C. at 1 atm    comprises a polymer or a copolymer of oxyethylene and/or    oxypropylene, and has a polymerization degree of 70 or more.-   (8) The antifungal medicinal composition according to any one of (1)    to (7), wherein the compound represented by the general formula (1)    comprises    (E)-[4-(2,4-dichlorophenyl)-1,3-dithiolan-2-ylidene]-1-imidazolyl    acetonitrile (Compound 1).-   (9) The antifungal medicinal composition according to any one of (1)    to (8), further comprising a surfactant.-   (10) The antifungal medicinal composition according to (9), wherein    the surfactant comprises an anionic surfactant.-   (11) The antifungal medicinal composition according to (10), wherein    the anionic surfactant comprises alkyl sulfate which may have a    polyoxyethylene group and/or alkyl phosphate which may have a    polyoxyethylene group.-   (12) The antifungal medicinal composition according to any one    of (1) to (11), further comprising acetone or methyl ethyl ketone as    an organic solvent.-   (13) The antifungal medicinal composition according to any one    of (1) to (12), wherein a coating film having plastic property is    formed when the antifungal medicinal composition is applied to an    application target.-   (14) The antifungal medicinal composition according to (13), wherein    the coating film having plastic property shows a glass state having    viscosity.-   (15) The antifungal medicinal composition according to (13) or (14),    wherein the antifungal medicinal composition is capable of    recoating.-   (16) The antifungal medicinal composition according to any one    of (13) to (15), wherein the coating film of the antifungal    medicinal composition is removable with swelling means using an    aqueous solvent and means for physical scratching.-   (17) The antifungal medicinal composition according to any one    of (13) to (16), wherein the antifungal medicinal composition is    used for an extensively keratinized portion of skin or nail or a    skin-thickened portion around foot as an application target.-   (18) A method of producing an antifungal medicinal composition    having (1) one or two or more selected from the group consisting of    ethyl cellulose, hydroxypropyl methylcellulose phthalate, and an    acrylic resin emulsion, (2) a polymer or copolymer of oxyethylene    and/or oxypropylene, and (3) an antifungal compound represented by a    general formula (1) and/or a physiologically acceptable salt    thereof, comprising:    -   dissolving alkyl sulfate which may have a polyoxyethylene group        and/or alkyl phosphate which may have a polyoxyethylene group        and the polymer or copolymer of oxyethylene and/or oxypropylene        in a solvent containing acetone or methyl ethyl ketone;    -   adding and dissolving in the solution the one or two or more        selected from the group consisting of ethyl cellulose,        hydroxypropyl methylcellulose phthalate, and an acrylic resin        emulsion; and    -   adding and dissolving in the solution the antifungal compound        represented by the general formula (1) and/or the        physiologically acceptable salt thereof.        (In the formula, R represents an alkyl group having 1 to 8        carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, a        methylene group, a lower alkenyl group, a halogen atom, a lower        alkyl group substituted with a lower alkoxy group or a lower        alkylthio group, or a group represented by a general formula (2)        below.)        (In the formula, R₁ represents a hydrogen atom, a halogen atom,        a linear- or branched-chain lower alkyl group, a lower alkoxy        group, a haloalkoxy group, or a methylenedioxy group, and m        represents an integral number of 1 to 3.)

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing a sample charge of a Franz type cell.

FIG. 2 is a diagram representing the results of Example 6.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in detail.

The antifungal medicinal composition of the present invention ischaracterized by including (1) a film-forming agent, (2) a water-solubleplasticizer in the form of a solid or a paste at 20° C. at 1 atm, and(3) an antifungal compound represented by the general formula (1) and/ora physiologically acceptable salt thereof.

The film-forming agent in the antifungal medicinal composition of thepresent invention may be one generally used for medicinal compositionsor the like, and preferable examples thereof include one insoluble orpoor soluble in water.

Here, the term “insoluble or poor soluble in water” means that thesaturated concentration of an agent is about 1 g/10 L, preferably 1 g/50L or less with reference to water at 20±5° C.

Preferable examples of such a film-forming agent include: alkylcelluloses represented by ethyl cellulose and hydroxypropylmethylcellulose phthalate; and acrylic resin-based emulsions such as onecommercially available from Higuchi Shokai Co., Ltd. by the name ofEudragit (registered trademark) NE30D, which is a dispersion liquid ofethyl acrylate/methyl methacrylate copolymer. Each of them may beindependently used, or two or more of them may be used in combination.The use of ethyl cellulose alone of those is particularly preferable.

A preferable content of the film-forming agent in the antifungalmedicinal composition of the present invention is preferably 0.1 to 10%by weight in volume, more preferably 0.3 to 5% by weight in volume intotal with respect to the whole amount of the medicinal composition.This is because a coating film having a sufficient strength cannot beobtained when the amount of the film-forming agent is excessively lowand the transfer of a drug may be inhibited when the film-forming agentis provided in an excess amount.

Examples of a water-soluble plasticizer in the form of a solid or apaste at 20° C. at 1 atm, which can be incorporated in the medicinalcomposition of the present invention, include a polymer or a copolymerof oxyalkylene such as oxyethylene or oxypropylene. A polymer or acopolymer having a larger polymerization degree is preferable. Theoxyalkylene is preferably one having 1 to 4 carbon atoms, morepreferably oxyethylene and/or oxypropylene.

A preferable polymerization degree of the polyoxyalkylene is preferably70 or more in total. The polymerization degree is at least 80 or more ifthere is oxyethylene alone, and is at least 70 or more if there isoxypropylene alone. A preferable combination between oxyethylene andoxypropylene is such that the polymerization degree of oxypropylene is30 to 80, the polymerization degree of oxyethylene is 35 to 400, and thesum of them is 70 or more.

Copolymers each having oxyethylene and oxypropylene are more preferable.Of those, one having a polyoxyethylene chain having a polymerizationdegree of 100 to 300 and a polyoxypropylene chain having apolymerization degree of 25 to 80 is still more preferable.

In addition, the oxyalkylene polymer or copolymer may be independentlyincorporated or may be incorporated in combination with another one.However, when two or more of them are combined, the mixture of such acombination should be kept in the form of a solid or paste at 20° C. at1 atm.

Of the combinations of the plasticizers, particularly preferable is acopolymer that contains only polyoxyethylene polyoxypropylene ethercontaining a polyoxyethylene portion having a polymerization degree of140 to 180 and a polyoxypropylene portion having a polymerization degreeof 20 to 40.

A preferable content of the plasticizer in the antifungal medicalcomposition of the present invention is preferably 1 to 10% by weight involume, more preferably 3 to 8% by weight in volume in total withrespect to the whole amount of the medicinal composition. Furthermore,the content of the plasticizer is preferably 1 to 10 folds, morepreferably 3 to 8 folds with respect to the content of the film-formingagent.

The antifungal composition of the present invention is represented bythe general formula (1) described above. A compound in which R in thegeneral formula (1) is represented by the general formula (2) isparticularly preferable. Concretely, preferable compounds represented bythe general formula (1) include(−)-(E)-[4-(2,4-dichrolophenyl)-1,3-dithioran-2-ylidene]-1-imidazolylacetonitrile (Compound 1),(+)-(E)-[4-(2-chlorophenyl)-1,3-dithioran-2-ylidene]-1-imidazolylacetonitrile (Compound 2), and lanoconazole. Those compounds are knownin the art, and thus the production methods and antifungalcharacteristics thereof have been already known in the art. JP 62-93227A can be referred. An optically active substance or a racemic body canbe used for such a compound. The optically active substance and the (−)body thereof are particularly preferable.

In addition, the “physiologically acceptable salt thereof” is notspecifically limited as far as it is physiologically acceptable, andpreferable examples thereof include: mineral acid salts such ashydrochloride, nitrate, sulfate, and phosphate; organic acid salts suchas citrate, oxalate, lactate, and acetate; and sulfuric acid-containingacid chlorides such as mesilate and tosylate. In terms of safety andsolubility, hydrochloride is more preferable.

The antifungal compound represented by the general formula (1) and/or aphysiologically acceptable salt thereof may be independently used aloneor two or more different types thereof may be used in combination.

The content of the antifungal compound represented by the generalformula (1) and/or the physiologically acceptable salt thereof in theantifungal medicinal composition of the present invention is preferably0.1 to 30% by weight in volume, more preferably 0.5 to 15% by weight involume in total with reference to the total amount of the medicinalcomposition. The amount of the antifungal compound may be determined inconsideration of its relation to the characteristics of a coating filmgenerated.

The medicinal composition of the present invention may include anycomponents generally used in dermatological external preparations inaddition to the essential components described above.

Examples of such components include: hydrocarbons such as vaselline andmicrocrystalline wax; esters such as jojoba oil and spermaceti;triglycerides such as beef tallow and olive oil; higher alcohols such ascetanol and oleyl alcohol; fatty acids such as stearic acid and oleicacid; alcohols such as ethanol and isopropanol; polyvalent alcohols suchas glycerine and 1,3-butanediol; water; nonionic surfactants; anionicsurfactants; cationic surfactants; amphoteric surfactants; ethanol;thickeners such as carbopol; antiseptics; UV absorbers; antioxidizingagents; pigments; powders; and organic solvents.

Of those, components particularly preferable to be incorporated in themedicinal composition of the present invention include the anionicsurfactants and the organic solvents.

In addition, the anionic surfactants are preferable in that each of themhas an action of accelerating the penetration of a drug into the nail orthe hardened portion of the skin. Each of the anionic surfactants may beused alone or two or more of the anionic surfactants may be used incombination.

Any of sulfate anionic surfactants and phosphorous anionic surfactantscan be used as an anionic surfactant, and the anionic surfactant mayhave a polyoxyethylene chain or not. More preferably, alkyl sulfatewhich may have a polyoxyethylene group and/or alkyl phosphate which mayhave a polyoxyethylene group can be mentioned. Alkyl sulfate esterand/or polyoxyethylene-added alkyl triphosphate ester is/are still morepreferable. A total number of added moles of the polyoxyethylene isparticularly preferably 2 to 16. The alkyl group is preferably onehaving 10 to 20 carbon atoms. More specifically, preferable examples ofthe alkyl group include a lauryl group, a palmityl group, and a stearylgroup. Particularly preferable examples of a combination of alkyl groupsinclude a configuration containing both lauryl sulfate andtripolyoxyethylene (referred to as triPOE)(4) lauryl ether phosphate.Furthermore, preferable examples of the salts of those anionicsurfactants include: alkali metal salts of sodium, potassium, and thelike; organic amine salts such as monoethanol amine, triethanol amine,and triethyl amine; ammonium salts; and salts of basic amino acids suchas arginine and lysine. Of those, the alkyl metal salts are preferableand sodium salt is particularly preferable.

A preferable content of the anionic surfactant in the antifungalmedicinal composition of the present invention is 0.5 to 10% by weightin volume, more preferably 1 to 5% by weight in volume in total withrespect to the total amount of the medicinal composition. Particularlypreferable is a configuration containing 1 to 5 parts by weight oflauryl sulfate and 0.5 to 3 parts by weight of triPOE(4) lauryl etherphosphate with respect to 100 parts by volume of the antifungalmedicinal composition of the present invention.

It is preferable that the antifungal medicinal composition of thepresent invention contain a polar organic solvent because of an increasein solubility of the antifungal compound represented by the abovegeneral formula (1).

Such an organic solvent is preferably one containing ketones, andexamples thereof include one containing acetone or methyl ethyl ketone.In particular, an organic solvent containing methyl ethyl ketone ispreferable.

A preferable content of the organic solvent in the antifungal medicinalcomposition of the present invention is 50 to 90% by volume with respectto the total amount of the medicinal composition (hereinafter, the samewill be applied). In this composition, a preferable content of theketones is 10 to 50% by volume. In addition, when an alcohol such asethanol is additionally included, a preferable content of the alcohol is20 to 60% by volume.

The medicinal composition of the present invention can be produced bytreating the above essential components and arbitrary components inaccordance with a usual method.

The medicinal composition thus obtained of the present invention forms acoating film having plastic property when it is applied to anapplication target. The coating film is in a viscous glass state. Morespecifically, the coating film itself is in the form of a solid but itis in a state of allowing the components to move inside the coatingfilm.

The coating film is a film on which additional films can be applied.That is, for the purpose of continuing the treatment, when the medicinalcomposition of the present invention is administered again to form acoating film, the coating film previously applied and dried does notprevent the movement of a drug in the new coating to an affected area.

In addition, when the medicinal composition of the present invention isapplied to the affected area of the nail or skin, unlike aconventionally known lacquer preparation, the coating film is hardlyremoved in general but it can be removed by swelling means using anaqueous solvent and means for physically scratching the coating film.Concretely, under a humidity condition with water or the like, thecoating film made of the medicinal composition of the present inventioncan be easily removed by scratching the coating film with an appliedsurfactant such as soap as required.

Furthermore, the coating film is in a glass state, so the movement of adrug from the coating film to the affected area can easily occur. As aresult, the drug can be always supplied to the affected area at apredetermined concentration. Therefore, the drug availability rises ascompared to the normal lacquer preparation. For this reason, theantifungal medicinal composition of the present invention can beeffectively used as external application for the treatment of fungaldiseases in the excessive keratinized portion of the skin and thethickened portion of the skin around the foot where the administrationeffect of the general antifungal medicinal composition for externalapplication is hardly obtained. Consequently, the antifungal medicinalcomposition of the present invention can be used to the affected area ofthe excessive keratinized portion of the nail or skin, or the thickenedskin portion around the foot.

Furthermore, fungi to be targeted with the antifungal medicinalcomposition of the present invention include Trichophyton(Trichophyton), a causative organism of candidiasis (Candida), acausative organism of cryptospolidiosis (cryptosporidium), and yeasts(Aspergillus).

The medicinal composition of the present invention can be produced bymeans of the general procedures. A preferable production example in apreferred embodiment will be described below.

For the production of an antifungal medicinal composition including: (1)one or two or more selected from the group consisting of ethylcellulose, hydroxypropyl methylcellulose phthalate, and an acrylic resinemulsion; (2) a polymer or copolymer composed of oxyethylene and/oroxypropylene, and (3) an antifungal compound represented by the generalformula (1) and/or a physiologically acceptable salt thereof, alkylsulfate which may have a polyoxyethylene group and/or alkyl phosphatewhich may have a polyoxyethylene group and the polymer or copolymercomposed of oxyethylene and/or oxypropylene are dissolved in a solventcontaining acetone or methyl ethyl ketone. In this solution,furthermore, the one or two or more selected from the group consistingof ethyl cellulose, hydroxypropyl methylcellulose phthalate, and anacrylic resin emulsion is/are added and dissolved, followed by addingand dissolving the antifungal compound represented by the generalformula (1) and/or the physiologically acceptable salt thereof. Theproduction according to such a method allows the pharmaceuticalmanufacturing of the antifungal composition represented by the generalformula (1) in a stable manner without causing crystal even in the caseof using a water-containing solvent.

Consequently, a preferable production method of the antifungal medicinalcomposition of the present invention can be provided.

EXAMPLES

Hereinafter, the present invention will be described concretely withreference to examples. However, the present invention is not limited tothese examples.

Furthermore, the abbreviations in each of examples and tables representthe following.

-   -   HP-55: Hydroxypropyl methylcellulose phthalate    -   Pluronic F-68: Polyoxyethylene (160) polyoxypropylene (30)        glycol    -   Macrogol 200: Polyethylene glycol 200    -   SDS: Sodium lauryl sulfate    -   TLP-4: Tripolyoxyethylene (4) lauryl ether sodium phosphate

Example 1

According to the formulation shown in Table 1 below, the antifungalmedicinal composition of the present invention was produced. Thecomponents a were stirred and solubilized. Then, the component b wasadded and solubilized, and the component c was further added andsolubilized, followed by the addition of the component d. Subsequently,the component e was added in order to adjust the pH of the mixture to pH6, followed by the addition of the component f to make the total volumeup to 100 ml. Consequently, an antifungal medicinal composition wasobtained. TABLE 1 Components a Methyl ethyl ketone 35 mL Ethanol 35 mLPluronic F-68 5 g Sodium lauryl sulfate 2 g b Ethyl cellulose 1 g cCompound 1 2 g d Water 15 g e Phosphoric acid Optimum dose f EthanolMaking total volume up to 100 ml

Examples 2 to 4

The components a to f were added in the same order as that of Example 1to prepare antifungal compositions of the present invention shown inTable 2 below. In addition, as shown in Table 2, comparative examples ofthe comparable technologies which did not belong to the antifungalmedicinal composition of the present invention were also prepared. TABLE2 Compar- Compar- Compar- Comparative Comparative Comparative ativeative ative Components Example 2 Example 3 Example 4 Example 1 Example 2Example 3 Example 4 Example 5 Example 6 a Methyl ethyl ketone   35 mL  10 mL   10 ml   25 mL   35 mL   35 mL   35 mL   10 mL   10 mL PluronicF-68  5.0 g  5.0 g  5.0 g  5.0 g — — — — — Macrogol 200 — — — — —  5.0 g— — — Octyl dodecanol — — — — — —  5.0 g — — SDS —  2.0 g —  2.0 g — — — 2.0 g — TLP-4  1.0 g —  1.0 g —  1.0 g  1.0 g  1.0 g —  1.0 g b Ethylcellulose  1.0 g  4.0 g — —  1.0 g  1.0 g  1.0 g  4.0 g — HP-55 — —  4.0g — — — — —  4.0 g c Compound 1  5.0 g  1.0 g  1.0 g  2.0 g  5.0 g  5.0g  5.0 g  1.0 g  1.0 g d Purified water 15.0 g 15.0 g 15.0 g 15.0 g 15.0g 15.0 g 15.0 g 15.0 g 15.0 g e Phosphoric acid Optimum Optimum OptimumOptimum Optimum Optimum Optimum Optimum Optimum (adjusted to pH 6) dosedose dose dose dose dose dose dose dose a, f Absolute ethanol OptimumOptimum Optimum Optimum Optimum Optimum Optimum Optimum Optimum dosedose dose dose dose dose dose dose dose Total  100 mL  100 mL  100 mL 100 mL  100 mL  100 mL  100 mL  100 mL  100 mL

Example 5

The antifungal medicinal compositions for external application of thepresent invention of Examples 1 to 4 and the antifungal medicinalcompositions for external application of Comparative Examples 1 to 6were investigated for characteristics of a coating film resulting fromthe application on nails.

As for the characteristics of the coating film, evaluation items weredefined as: a time period (second) from the drying after application tothe film formation; the condition of the coating film at 12 hours fromthe application; and the removability of the coating film with water at12 hours from the application, respectively.

The criteria for the coating film conditions were no removal of thecoating film;

-   -   ⊚: partial removal of the coating film;    -   ∘: almost half removal of the coating film; and    -   x: more than half removal of the coating film.

The criteria for the removability were

-   -   ⊚: easily washing out the coating film;    -   ∘: requiring scouring to wash out the coating film; and    -   x: impossible to wash out the coating film by means of running        water.

The results are shown in Table 3. The results show that the antifungalexternal application of the present invention is excellent in retainingthe coating film while the coating film can be easily removed throughwater washing TABLE 3 Conditions after Washing Sample Drying time 12hours efficiency Example 1 45 seconds ⊚ ⊚ Example 2 40 seconds ⊚ ⊚Example 3 65 seconds ⊚ ⊚ Example 4 67 seconds ⊚ ⊚ Comparative 40 secondsX ⊚ Example 1 Comparative 50 seconds ⊚ X Example 2 Comparative 50seconds X ◯ Example 3 Comparative 60 seconds X ◯ Example 4 Comparative60 seconds ⊚ X Example 5 Comparative 50 seconds ⊚ X Example 6

Example 6

The antifungal medicinal compositions for external preparation ofExamples 3 and 4 described above and the antifungal medicinalcompositions for external preparation of Comparative Examples 5 and 6described above were investigated in terms of the drug release fromtheir coating films formed using a Franz type diffusion cell.

As shown in FIG. 1, 200 μl of a pharmaceutical agent were dropped onto aPET sheet (reference numeral 1) to form a coating film and then adialysis membrane (reference numeral 2) was laminated on this sheet. Thedialysis membrane was directed to a receptor and then mounted on theFranz type diffusion cell. Subsequently, the receptor was filled with0.01 N hydrochloric acid and samples were then obtained from thereceptor at regular time intervals to determine the level of thepharmaceutical agent in the liquid in the receptor using HPLC.

The results are shown in FIG. 2. As is evident from FIG. 2, thecompositions of Examples 3 and 4 have excellent characteristics of drugrelease compared with those of Comparative Examples 5 and 6.

In consideration of those results together with the results of the aboveexamples, it is found that the antifungal medicinal composition of thepresent invention keeps a drug-storing film intact over an extended timeperiod and releases the drug from the film effectively to enhance thetherapeutic effects of the drug, while it retains the ability of beingeasily removed when it is needed to be removed.

Example 7 In Vitro Test for Pharmacometrics

A cylindrical silicone ring was fixed on the surface of nail plate(human) with a silicon bond, and the resultant was placed on anutrient-free agar medium containing 2×10⁵/ml of conidiospores ofTrichophyton mentagrophytes, followed by incubating the medium at 28° C.for 7 days.

After incubation, the growth of bacteria on the nail bed side wasconfirmed and then each agent, 51, was administered in the cylindricalring. After administration, the resultant was incubated at 28° C. for 7days and then the nail was removed from the medium, followed by lightlyscratching the nail bed side with a needle spreader.

On this occasion, the nail waste caused was seeded on a Sabouraud's agarmedium and then incubated at 28° C. for 14 days, followed by confirmingthe cbacterial growth. The nail, which did not show the bacterialgrowth, was recognized as bacteria negative. The ratio (%) of thebacteria negative nail waste was determined. The results are shown inTable 4.

As is evident from the results, the antifungal medicinal composition ofthe present invention exerts excellent abilities of storing andreleasing a drug and also exerts excellent effects on fungal diseaseswhich are hardly cured by means of the general external applicationtherapy owing to the inhibition of thick keratin such as a nail. TABLE 4Comparative Comparative Example 2 Example 2 Example 4 Name of drugCompound 1 Compound 1 Compound 1 Level of drug  5%   5%   5% Bacterialnegative 100% 33.3% 33.3% ratio (n = 6)

Examples 8 and 9

The components a to f (except e) were added in the same order as that ofExamples 1 to 4 to prepare the antifungal medicinal compositions(Examples 8 and 9) of the present invention shown in Table 5 below. Inaddition, as shown in Table 5, the antifungal medicinal compositions ofComparative Examples 7 to 9 were prepared.

Those compositions were investigated for drying time and conditions andwashing efficiency after 12 hours. The results were shown in Table 6.TABLE 5 Comparative Comparative Comparative Components Example 8 Example9 Example 7 Example 8 Example 9 a Methyl ethyl   35 mL   35 mL   35 mL  35 mL   35 mL ketone Pluronic F-68   5 g   3 g   5 g SDS   2 g   0 g  2 g   0 g   2 g b Ethyl cellulose  1.5 g   0 g  1.5 g   0 g  1.5 gEthy lacrylate/  1.5 g  1.5 g methyl methacrylate copolymer dispersion(solid) c Lanoconazole  2.0 g  2.0 g  2.0 g  2.0 g   0 g d Purifiedwater   15 g   15 g   15 g   15 g   15 g a, f Absolute ethanol OptimumOptimum Optimum Optimum Optimum dose dose dose dose dose Total  100 mL 100 mL  100 mL  100 mL  100 mL

TABLE 6 Washing Sample Drying time Conditions after 12 hours efficiencyExample 8 40 seconds ⊚ ⊚ Example 9 50 seconds ⊚ ⊚ Comparative 40 seconds⊚ X Example 7 Comparative 50 seconds ⊚ X Example 8 Comparative 40seconds ⊚ X Example 9

Example 10

The in vitro effects of the antifungal medicinal composition of thepresent invention were evaluated by the same way as that of Example 7,except that incubation was carried out at 28° C. for 14 days. Theresults are shown in Table 7.

Therefore, it is evident that the medicinal composition of the presentinvention has an excellent antifungal action. In addition, it is alsofound that the compounds represented by the general formula (1), inparticular Compound 1, are particularly preferable for a pharmaceuticalpreparation. TABLE 7 Comparative Example 1 Example 8 Example 9 Name ofdrug Compound 1 Lanoconazole None Level of drug  2%   2% None Bacterialnegative 100% 83.3% 0% ratio (n = 6)

Example 11

The medicinal composition of the present invention was prepared by thesame way as that described above, except that the concentration ofCompound 1 was changed. TABLE 8 Components a Methyl ethyl ketone 35 mLEthanol 35 mL Pluronic F-68 5 g Sodium lauryl sulfate 2 g b Ethylcellulose 1 g c Compound 1 5 g d Water 15 g e Phosphoric acid Optimumdose f Ethanol Making total volume up to 100 ml

Example 12

The medicinal composition of the present invention was prepared by thesame way as that described above, except that the concentration ofCompound 1 was changed. TABLE 9 Components a Methyl ethyl ketone 35 mLEthanol 35 mL Pluronic F-68 5 g Sodium lauryl sulfate 2 g b Ethylcellulose 1 g C Compound 1 2.5 g d Water 15 g e Phosphoric acid Optimumdose f Ethanol Making total volume up to 100 ml

Example 13

The medicinal composition of the present invention was prepared by thesame way as that described above, except that the concentration ofCompound 1 was changed. TABLE 10 Components a Methyl ethyl ketone 35 mLEthanol 35 mL Pluronic F-68 5 g Sodium lauryl sulfate 2 g b Ethylcellulose 1 g c Compound 1 1.25 g d Water 15 g e Phosphoric acid Optimumdose f Ethanol Making total volume up to 100 ml

Example 14

Reference Examples, in which the medicinal compositions of Examples 11to 13 described above and Compound 1 of Example 11 were substituted withethanol respectively, were subjected to a primary skin irritation test.

That is, the backs of rabbits (New Zealand White species, six animalsper group) were dehaired to form 6 areas of 3 cm×3 cm. On each of thoseareas, a lint cloth soaked with 0.5 ml of the sample was pasted and thencovered with Parafilm and a bandage, followed by conducting a 24-hourclosed patch. One of the areas was not patched and treated. At one hourafter removal of the patch, a skin reaction was observed in terms of twoitems: (1) erythema and crust formation and (2) edema formation.

The erythema and crust formation were evaluated on the basis of thefollowing evaluation criteria/

Score 0: no erythema, Score 1: minimum erythema, Score 3: clearerythema, and Score 4 middle to strong erythema, mild crust formation inerythema with strong dark red.

The edema formation was evaluated on the basis of the followingcriteria.

Score 0: no edema, Score 1: minimum edema; Score 2, clear edema, Score3: medium edema, and Score 4: strong edema.

The results show that any of the sampled areas was Score 0 for each of(1) erythema and crust formation and (2) edema formation. As is evidentfrom those results, the safety in dermatological external application ofthe present invention was confirmed.

INDUSTRIAL APPLICABILITY

According to the present invention, a medicinal composition useful forexternal application in the treatment of a fungal infection reaching thelower part of a thick keratin layer can be provided.

1. An antifungal medicinal composition, comprising: (1) a film-formingagent; (2) a water-soluble plasticizer in a form of a solid or a pasteat 20° C. at 1 atm; and (3) an antifungal compound represented by ageneral formula (1) and/or a physiologically acceptable salt thereof

wherein, R represents an alkyl group having 1 to 8 carbon atoms, acycloalkyl group having 3 to 6 carbon atoms, a methylene group, a loweralkenyl group, a halogen atom, a lower alkyl group substituted with alower alkoxy group or a lower alkylthio group, or a group represented bya general formula (2) below

wherein, R₁ represents a hydrogen atom, a halogen atom, a linear- orbranched-chain lower alkyl group, a lower alkoxy group, a haloalkoxygroup, or a methylenedioxy group, and m represents an integral number of1 to
 3. 2. The antifungal medicinal composition according to claim 1,wherein the film-forming agent has low water solubility or waterinsolubility.
 3. The antifungal medicinal composition according to claim2, wherein the film-forming agent having low water solubility or waterinsolubility comprises one or two or more selected from the groupconsisting of ethyl cellulose, hydroxypropyl methylcellulose phthalate,and an acrylic resin emulsion.
 4. The antifungal medicinal compositionaccording to claim 2, wherein the film-forming agent having low watersolubility or water insolubility comprises ethyl cellulose.
 5. Theantifungal medicinal composition according to claim 1, wherein thewater-soluble plasticizer in the form of a solid or a paste at 20° C. at1 atm comprises a compound having a polyoxyethylene group and/or apolyoxypropylene group.
 6. The antifungal medicinal compositionaccording to claim 5, wherein the water-soluble plasticizer in the formof a solid or a paste at 20° C. at 1 atm comprises an oxyethyleneoxypropylene copolymer.
 7. The antifungal medicinal compositionaccording to claim 5, wherein: the film-forming agent having low watersolubility or water insolubility comprises one or two or more selectedfrom the group consisting of ethyl cellulose, hydroxypropylmethylcellulose phthalate, and an acrylic resin emulsion; and thewater-soluble plasticizer in the form of a solid or a paste at 20° C. at1 atm comprises a polymer or a copolymer of oxyethylene and/oroxypropylene, and has a polymerization degree of 70 or more.
 8. Theantifungal medicinal composition according to claim 1, wherein thecompound represented by the general formula (1) comprises(E)-[4-(2,4-dichlorophenyl)-1,3-dithiolan-2-ylidene]-1-imidazolylacetonitrile (Compound 1).


9. The antifungal medicinal composition according to claim 1, furthercomprising a surfactant.
 10. The antifungal medicinal compositionaccording to claim 9, wherein the surfactant comprises an anionicsurfactant.
 11. The antifungal medicinal composition according to claim10, wherein the anionic surfactant comprises alkyl sulfate which mayhave a polyoxyethylene group and/or alkyl phosphate which may have apolyoxyethylene group.
 12. The antifungal medicinal compositionaccording to claim 1, further comprising acetone or methyl ethyl ketoneas an organic solvent.
 13. The antifungal medicinal compositionaccording to claim 1, wherein a coating film having plastic property isformed when the antifungal medicinal composition is applied to anapplication target.
 14. The antifungal medicinal composition accordingto claim 13, wherein the coating film having plastic property shows aglass state having viscosity.
 15. The antifungal medicinal compositionaccording to claim 13, wherein the antifungal medicinal composition iscapable of recoating.
 16. The antifungal medicinal composition accordingto claim 13, wherein the coating film of the antifungal medicinalcomposition is removable with swelling means using an aqueous solventand means for physical scratching.
 17. The antifungal medicinalcomposition according to claim 13, wherein the antifungal medicinalcomposition is used for an extensively keratinized portion of skin ornail or a skin-thickened portion around foot as an application target.18. A method of producing an antifungal medicinal composition having (1)one or two or more selected from the group consisting of ethylcellulose, hydroxypropyl methylcellulose phthalate, and an acrylic resinemulsion, (2) a polymer or copolymer of oxyethylene and/or oxypropylene,and (3) an antifungal compound represented by a general formula (1)and/or a physiologically acceptable salt thereof, comprising: dissolvingalkyl sulfate which may have a polyoxyethylene group and/or alkylphosphate which may have a polyoxyethylene group and the polymer orcopolymer of oxyethylene and/or oxypropylene in a solvent containingacetone or methyl ethyl ketone; adding and dissolving in the solutionthe one or two or more selected from the group consisting of ethylcellulose, hydroxypropyl methylcellulose phthalate, and an acrylic resinemulsion; and adding and dissolving in the solution the antifungalcompound represented by the general formula (1) and/or thephysiologically acceptable salt thereof

wherein, R represents an alkyl group having 1 to 8 carbon atoms, acycloalkyl group having 3 to 6 carbon atoms, a methylene group, a loweralkenyl group, a halogen atom, a lower alkyl group substituted with alower alkoxy group or a lower alkylthio group, or a group represented bya general formula (2) below

wherein, R₁ represents a hydrogen atom, a halogen atom, a linear- orbranched-chain lower alkyl group, a lower alkoxy group, a haloalkoxygroup, or a methylenedioxy group, and m represents an integral number of1 to 3.